What to Do?

i am a mom of 2 and stepmom of 1. 9 year old stepson came to live with my husband and our 2 boys about 5 months ago and it has not been easy. i knew upfront that the stepmom/stepchild relationship is not gonna be a smooth ride but what do i do when i'm caught between a husband and mother-in-law who seem to believe i am here to replace stepson's mom AND a stepson who does not want to (at least at the moment) see me in a mommy role? i am constantly worrying about how will certain actions be seen. an example - stepson has made it clear by his actions that he doesn't want physical affection from me like hugs, holding his hands etc but i still want to hug, hold my 5 yr old and 1 yr old . . . if i don't hug stepson i made to feel as if i don't like him or something or i am favoring my 2 biological kids. if i do, he is looking away and doesn't hug back. do i keep hugging him in the hopes that he will one day return the favor or do i tell my husband i have tried and it doesn't seem like the child is interested?